NEW YORK (CNNMoney) -- Hospitals are supposed to be the place where the sick get well. They can also be where the sick get sicker, thanks to the virulent bacteria and viruses that live there.

At any given time, 1 in 20 hospital patients is battling an infection that they got on site, according to the Centers for Disease Control. Hospitals now pay greater attention to hand hygiene -- Purell dispensers have become ubiquitous -- but their main infection control methods haven't changed much for decades. Most rooms are still disinfected by housekeepers armed with chemical cleaners.

Enter the Xenex,a mobile, robotic device that combats germs with blasts of light. It looks like Star Wars' R2D2 with a handle, but it's a killing machine -- if you're a microorganism. Set it loose in a hospital room and it will chirp and click its way through a cleaning routine of strobe-like pulses. Those flashes are what's called "pulsed xenon UV," a type of ultraviolet light that sterilizes and kills microbiological contaminants.

Epidemiologists Julie Stachowiak and Mark Stibich developed the technology that powers the Xenex at the Houston Technology Center. To commercialize the system, they needed to build a business. That's where Brian Cruver, a former Enron trader, came in. After starting his career at the company that became infamous for its corruption -- a story Cruver told in the book Anatomy of Greed -- Cruver shifted his career toward entrepreneurship.

"I wanted to get involved with ventures that did some good," he says.

Cruver joined Xenex in 2009 as the company's CEO. The Austin-based venture now has 30 employees and has raised about $5 million from investors.

The Xenex disinfects a hospital room in about five to 10 minutes, focusing on high-touch surfaces like tray tables, telephones, and bedrails. After housekeepers finish cleaning a room, they wheel the machine in and hit go. "It's easier to use than a vacuum cleaner," Cruver says.

Watch the Xenex robot in action

It also works. At Cooley Dickinson Hospital in Northampton, Mass., 1 in 129 patients came down a hospital-acquired infection in 2010. Last January, Cooley began using the Xenex device. It subsequently saw a 67% drop in infections from C. diff, a toxic superbug that can cause diarrhea, sepsis and death.

"We think we might have saved five lives and prevented two colostomies," says Dr. Joanne Levin, medical director of Cooley's infection prevention program. Dickinson now has two Xenex machines and is getting a third this year, with the goal of using it in every room.

An average-sized hospital, with about 120 beds, would need two Xenex devices to clean all its rooms. Each one costs about $80,000, and can be bought or leased.

That's not cheap -- but infections aren't either. It costs U.S. hospitals about $35 billion a year to treat hospital-acquired illnesses. The price tag for treating one case of a common bug, MRSA (methicillin-resistant Staphylococcus aureus), is about $28,000, according to Dr. Mary Jo Cagle, the chief quality officer of Cone Health, a five-hospital healthcare system in North Carolina.

Since four of Cone's hospitals began using the Xenex last January, the chain has reduced its incidence of MRSA infections by 35% hospital-wide, and lowered it to zero in the intensive care units.

"This has been a game-changer for us," Cagle says.

Xenex's market is potentially huge. In the U.S. alone there are about 5,800 hospitals. Xenex's technology is currently in around two dozen hospitals, and the company hopes to have it in 240 by the end of this year. It's also moving into Europe and Asia.

Ramanan Laxminarayan, director of the Center for Disease Dynamics, Economics & Policy in Washington D.C., says that as long as Xenex's technology is cost effective for hospitals, he sees little downside. "It already has an advantage in the marketplace because it doesn't require doctors or nurses to change their behavior or do more," he says.

Cone Health estimates that it has saved nearly $3 million by using the Xenex device.

"Rooms are cleaned faster and are safer now," Cagle says. "When you're talking about critically ill patients, just getting them into a room 15 minutes faster can mean the difference between life and death."